Flashcards
OCB02-1013-Root development and eruption
Flashcards do conjunto (24)
- 1When does the cervical loop become Herwig's Epithelial Root Sheath?Once the tooth crown mineralises, it grows down
- 2What are the three functions of HERS?1. Map out root sheath and boundaries?
2. Initiate root odontoblast differentiation
3. Disintegrate to initiate cementum/PDL formation - 3When does HERGS map out root sheath?Late bell stage
- 4What do molecules secreted from HERS target to initiate root odontoblast differentiation?Mesenchyme cells
- 5How does disintegration of HERS lead to cementum/PDL formation?Exposes mesenchyme cells in follicle to dentin
Cells differentiate into cementoblasts - 6Acellular cementum is...Thin, coronal 2/3 of root
- 7Cellular cementum is...Thick, apical 1/3 of root
- 8What happens to the remnants of HERS?Can reactivate/become tumours and cysts in adulthood
- 9How is the root apex formed? What is different about it in multi-cusp teeth?HERS grows in 90 degree angle towards apical foramen
HERS will connect in double root teeth to form two roots
HERS will separate root into 3 - 10What is the apical foramen?Where nerve/blood vessels get into dental pulp
- 11How does tooth eruption occur in deciduous teeth?1. Formation of the PDL
2. Fusion of layers into reduced enamel epithelium
3. Oral epithelium and reduced enamel epithelium forms the dental gingival junction
4. Bone reabsorbed at Gubernacular Cord to allow tooth eruption - 12Which cells secrete what to form the PDL?Fibroblasts secrete collagen which forms bundles
- 13Which layers form the reduced enamel epithelium?1. Outer enamel epithelium
2. Stellate reticulum
3. Stratum intermedium
4. Inner enamel epithelium - 14Why is there no bleeding during tooth eruption?Goes through epithelial cells (only mesenchyme cells are vascularised)
- 15What is the main cause of permanent tooth eruption?Alveolar bone remodelling:
-Osteoblasts form bone at tips of roots to PUSH teeth out - 16During permanent tooth eruption what occurs in the coronal 1/2 of the root?resorption by osteoclasts
- 17During permanent tooth eruption what occurs in the basal 1/2 of the root?bone formation by osteoblasts
expression of BMP2 for osteoblast differentiation - 18What controls bone resorption/creation at roots?Dental follicle by sending signals to recruit osteoclasts/blasts
- 19What other factors contribute to permanent tooth eruption?1. Root growth
2. PDL may accelerate eruption speed by pulling - 20NF1-C mutant micelack roots bc no odontoblast diffrentiation
- 21Which disorders have short roots?Dentin dysplasia type 1: DSPP gene
Sponastrine dysplasia - 22What is wrong in OFCD?abnormally long roots
mutation in BCOR gene so mesenchyme keeps being stem cells - 23Taurodontism caused by...failure of HERS to reorientate at proper level, so roots separate too low
- 24EDG (lacking or overexpressed) mutants have...variable root numbers
Informações
- Descrição
- -Hertwig’s root sheath and explain its function in root development. -how single and multirooted teeth form and how accessory root canals develop. -origin of epithelial cell rests. -stages of tooth eruption in teeth lacking predecessors. - reduced enamel epithelium and its role in the development of the junctional epithelium. - eruption, indicating its rates possible mechanisms whereby an eruptive force may be produced: tension versus pressure.
- Criado por
- Evian Chai
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- 46
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